초록 ▼

A control valve for a fluid actuator has a slide valve member mounted within a housing with an external knob on one end and a piston on the other end. The knob may be manually operated for resetting the piston. When the main flowline pressure reaches a high or low pressure outside the fluid pressure

A control valve for a fluid actuator has a slide valve member mounted within a housing with an external knob on one end and a piston on the other end. The knob may be manually operated for resetting the piston. When the main flowline pressure reaches a high or low pressure outside the fluid pressure operating range the piston is seated and fluid is exhausted from the actuator for effecting movement of the main valve member. The control valve is maintained in its exhaust position by a spring continuously urging the piston into a seated position. An annular seal engages the face of the piston in seated position to expose only a relatively small surface area of the piston to fluid pressure when the piston is seated and the control valve is in an exhaust position. Means are provided to permit a venting or bleeding of fluid around the piston in the seated position of the piston in the event of leakage of fluid past the annular seal or temporary unseating of the piston resulting from vibrations or the like.

대표청구항 ▼

A control valve structure for controlling fluid communication between a first fluid pressure source and a main valve actuator, said control valve structure comprising an elongated housing having a bore extending longitudinally thereof and a slide valve mounted within the bore for longitudinal moveme

A control valve structure for controlling fluid communication between a first fluid pressure source and a main valve actuator, said control valve structure comprising an elongated housing having a bore extending longitudinally thereof and a slide valve mounted within the bore for longitudinal movement, said slide valve having an external knob on one end and a piston on the other end, a spring urging the slide valve inwardly to a seated position of the piston, a detent to hold the slide valve in an out position when the knob is manually gripped and the slide valve is moved to the out position against the bias of the spring, port means in fluid communication with said bore and exposing the outer face of the piston to fluid pressure, means urging the detent out of engagement with the slide valve and releasing the slide valve when the outer face of the piston is exposed to a predetermined high pressure from said port means, and a resilient annular seal between the port means and the outer face of the piston exposing only a relatively small surface area of the piston to fluid pressure from said port means when the piston is in a seated position, said annular seal permitting the entire outer face of said piston to be exposed to fluid pressure from said port means when the piston is out of seated position.